Symptom Complex Index > Bilateral Recurrent Laryngeal Nerve Injury
Etiology
This syndrome results from an injury to both recurrent laryngeal nerves. It affects all of the intrinsic laryngeal muscles (thyroarytenoid, lateral cricoarytenoid, posterior cricoarytenoid, interarytenoid) except the cricothyroid. There may be varying degrees of paralysis since the injury may be incomplete, reinnervation may occur or reinnervation with synkinesis may occur. This disorderd reinnervation may cause isotonic contraction rather than functional contraction and movement. And in my experience reinnervation with synkinesis is common.
Diagnosis
History
Typical complaints
- onset
- abrupt loss of voice after surgery is the most typical presentation
- total thyroidectomy
- parathyroidectomy
- weak voice for several months initially
- The voice becomes “Mickey Mouse” like for a few weeks.
- Then the voice improves becoming nearly normal
- Or the voice may become somewhat unpredictable with unusual sounds coming out at strange times.
- Then breathing becomes tight with any exercise
- Episodes where they cannot breath - frequent laryngospasm, high pitched sounds while trying to breath. Frequently very noisy breathers at night.
- perfumes, odors or drinking may trigger episodes
Character of a patient with Bilateral Recurrent Laryngeal Nerve Injury
- poor voice early in illness
- often accepting of the surgeons recommendation to just wait and see for six months to a year
- often excellent voice late in recovery phase
- or a voice that is good but fades with use
- Talkativeness scale: whole range
Vocal capabilities
These findings will depend a great deal on when in the time course of the illness the patient presents for an exam.
- Speaking voice
- Early: whisper
- Late: clear but some sounds seem out of direct control of the patient
- Yelling voice
- Early: luffing sound (asynchronous vibration like a sail flapping in the wind) on loud phonation at low pitch early
- Late: good shout later in recovery
- Maximum phonation time
- Early: markedly reduced at anchor pitch (often less than 10 seconds)
- Late: normal
- Pitch range
- obligate falsetto (physical inability to phonate in other than falsetto register) This is the “Mickey Mouse” phase. This is the opposite of a superior laryngeal nerve injury where the TA and LCA provide tension at low pitch but the cricothyroid is unable to provide additional tension to raise the pitch. Here the cricothryoid is the main muscle helping to approximate the vocal folds.
- Vegetative sounds - cough
- Early: nonpercussive cough
- Late: may sound like a sick dog later as the vocal cords fail to relax after initial closure
Laryngeal Exam
- rigid laryngoscope
- may be in paramedian or lateralized position early
- complete immobility early
- decreased range of motion also possible
- because Interarytenoid may actively pull the affected side somewhat
- injury may be incomplete involving only a portion of the posterior or anterior branches of the recurrent laryngeal nerve
- reinnervation may be taking place
- almost essential to use video recording to slow down and analyze the motion of the arytenoids that is taking place
- bowing
- flexible laryngoscope
- same motion findings should be present
- Bilateral atrophy or noodle like vocal folds
- Capacious ventricle on the both sides
- Conus may also show some tissue loss
- abnormal configuration of posterior glottis even if vocal processes oppose each other
- some movement may make it difficult to separate out fixation form paralysis visually
- Laryngeal EMG (electromyogram) to assess which muscles are denervated and whether synkinesis is present
Treatment
This will depend on where in the time course of the injury and recovery the patient is.
Medical
Behavioral
Voice building exercises early in the post injury phase
- In its simplest form, this could amount to 10 minutes three times a day reading aloud as if projecting the voice to an audience.
- With this amount of dedication, there should be some improvement within three weeks if it is going to help at all.
- This would be most useful if there is evidence of reinnervation or incomplete paralysis.
Surgical
- Medialization with an in office injection early in the injury.
- Collagen
- Bovine collagen Zyplast by Mcghan Pharmaceuticals
- Human collagen Cymetra by LifeCell Corporation
- Patient information on injections
- Gelfoam - indicated for about 3 months of relief when the possibility of spontaneous neurologic recovery exists but presently off market because of a recall on the product 4/2001.
- Late in the injury when both vocal folds are together
- Traditionally
- Laser cordotomy
- Laser arytenoidectomy
- Tracheotomy
- some new thoughts I have tried
- Botox injection to selectively denervate some of the adductor muscles or alleviate laryngospasm
- Arytenoid lateralization via suture with accompanying medialization of the membranous portion of the vocal cord to improve airway while maintaining some voice.
- Selective denervation of the anterior branch of the recurrent laryngeal nerve
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